The effects of laser wavelength and particle size on heating and melting of gold nanoparticles dispersed in liquid

In this research, the heating process and melting of water surrounded homogenous gold nanospheres irradiated by nanosecond laser pulses at the wavelengths of 355, 532, 633, and 900 nm are studied. The estimation of absorbed energy by gold nanoparticles with radius range 1-40 nm and their maximum temperature is done using the absorption eciency of the nanoparticles at the corresponding laser wavelength. The dependency of the melting temperature of nanoparticles upon their size is also considered. It is seen that progress in the melting process strongly depends on the laser wavelength and particle size. The laser wavelength of 532 nm has been found appropriate for eective photothermal heating of a large gold nanoparticle. Controlling the laser irradiation wavelength is crucial to achieve the best conditions for the desired applications such as localized heating and nanowelding.